Optical disc recording method and optical disc drive

ABSTRACT

Because a series of data is recorded continuously, the recording quality of data recorded in course of recording cannot be evaluated. Accordingly, the laser output cannot be controlled properly and there are a deterioration and dispersion of the recording quality. Further, when the recording lasts for a long time, the temperature in the vicinity of laser rises due to the heat from the inside of a disc drive and the recording quality is deteriorated.  
     To solve this, a series of data to be recorded is split and recording is made intermittently in a split data unit. The recording quality is evaluated by reproducing the data recorded nearby before each split data is recorded using a duration and control is performed by reflecting the evaluation result in the laser output so that the recording quality can be maintained satisfactorily over a series of the whole data to be recorded. Further, control is performed so that good recording quality can be maintained even in the recording that lasts for a long time by stopping the function of each part that ought to be operated even at recording or reproduction inside the disc drive in the duration, thereby suppressing a temperature rise.

FIELD OF THE INVENTION

[0001] The present invention relates to an optical disc drive, andprovides an art for solving a problem that occurs when the optical discdrive records a series of data continuously.

BACKGROUND OF THE INVENTION

[0002] A conventional optical disc drive made recording in accordance ofa recording method specified in a standard. Further, even in a recordingmethod of a conventional disc drive, before recording was made, a testpattern was recorded in the trial write area on a disc using varioustypes of laser power and an output value that is suitable for laser wasfixed based on the reproduction result of the test pattern.

[0003] However, in the recording method as specified in the standard, aproblem occurred in some cases according to the type of the disc, theshape of the drive, or the data recorded in the disc.

[0004] Usually, the sensitivity of a disc to laser beam is not uniformover the whole disc surface. Further, laser has a characteristic thatthe laser is subject to the influence of ambient temperature by the heatthe laser itself emits and the heat generated from a disc dive circuitand the output changes.

[0005] Based on this characteristic, a recording method of Disc at Oncespecified in the standard and the point at issue are described.

[0006] This Disc at Once recording method is used, for example, whendata, such as a video and an audio, is recorded in a DVD-R and therecording data realizes reproduction compatibility in a DVD videoplayer. Further, this recording method specifies that data iscontinuously recorded without being interrupted halfway from theexternal surface to the internal surface of a disc.

[0007] Accordingly, in this recording method, recording must becontinued without evaluating the sufficient recording quality ofrecorded data until all data is recorded. The reason why the recordeddata cannot be evaluated sufficiently is that usually, a recording headand a reproducing head are integrated in an optical disc drive.

[0008] The most reliable method for evaluating recording quality is toreproduce recorded data. However, in a head that shares recording andreproduction, the reproduction can be made only when the recording isstopped. Accordingly, because a conventional optical disc drive cannotinterrupt the recording in the recording method, such as above Disc atOnce, reliable recording quality is not evaluated. Accordingly, it wasdifficult to maintain appropriate recording quality concerning the wholedata that was recorded.

[0009] When the size of a series of data to be recorded is large andcontinuous recording lasts for a long time in particular, sufficientrecording quality cannot be evaluated in course of recording.Accordingly, the laser output cannot be controlled appropriately andthere was a problem of the deterioration or unevenness of recordingquality. Further, because the temperature inside a disc drive becomesextremely high due to continuous recording, laser cannot be used undergood temperature characteristics. Accordingly, the maintenance of therecording quality was difficult. Further, the maintenance of therecording quality was difficult in a compact disc drive of which themounting of a cooling means, such as a fan, also causes a cost increaseand that has no room for space and is limited in a power supply.

[0010] There were some conventional disc drives, for example, asdisclosed in Japanese Unexamined Patent Publication No. 2001-34947, thatexecute recording and making adjustments so as to satisfy the optimumrecording condition evaluating recording quality. However, theseconventional disc drives made the adjustments between recording andrecording choosing a period during which data is not transferred from ahost machine connected to a disc drive.

[0011] However, when the data is transferred incessantly from the hostmachine, such as in Disc at Once recording, the recording must becontinued incessantly. Accordingly, it was difficult to make a recordingin a good recording condition after the recording quality is checkedsufficiently during that time.

[0012] This was a problem when real time data, such as a video and anaudio, is recorded in particular. When the real time data is recorded,the recording data itself that is recorded becomes an original source.That is, after all data have been recorded, it impossible to evaluaterecording quality evaluated, and to redo the recording from thebeginning if the recording quality is bad. Because of such reason, theconventional disc drive could not take corrective action for real timerecording sufficiently. Further, even in the case of non-real timerecording that enables undoing of recording, the time for undoing therecording occurs. In a medium, such as a DVD-R, in which a disc enablesrecording only once, a new disc had to be prepared and even costs waswasted.

[0013] As described above, when a series of data, such as Disc at Oncerecording, must be recorded continuously in particular, such Disc atOnce recording, it was difficult for a conventional disc drive tosatisfactorily maintain the recording quality of the whole recordeddata. Further, accordingly, the real time recording of a video and anaudio in which the recording data itself becomes an original source atonce is not suitable for a recording method, such as the Disc at Oncerecording, in which a series of data must be recorded continuously. Therecording of real time data into a disc, such as a DVD-R in particular,in which recording is enabled only once was difficult.

SUMMARY OF THE INVENTION

[0014] One issue of the present invention is to solve the above point atissue that occurs when data in which it specifies that a series of data,Disc at Once recording, is recorded continuously in a conventional discdrive is recorded.

[0015] Further, the other issue of the present invention is about tosolve is to realize the recording of real time data and the recordingfor a disc medium of which the recording is enabled only once in goodrecording quality by solving the above point at issue.

[0016] Accordingly, the present invention evaluates the recordingquality of data recorded at a moderate time in course of recording andreflects the result in the laser output. A conventional disc driverecords a series of data continuously as specified in a standard,whereas the present invention splits a series of data to be recorded andmakes a recording intermittently in a unit of split data. As a result,control is performed so that a series of data recorded can be producedin the same manner as when data was recorded continuously. Subsequently,control is performed so that the recording quality can be maintainedsatisfactorily over a series of the whole data to be recorded byreflecting the result in the laser output of the next data recordingbased on the recording state of the data reproduced by reproducing thedata that was recorded before each data that was split using a durationobtained by the intermittent recording is recorded. Further, control isperformed so that good recording quality can be maintained even in therecording lasting for a long time by stopping the function of each partinside a disc drive within the duration or disconnecting the power tosuppress the temperature rise inside the disc drive and therebydecreasing a laser output change. Moreover, a series of data in whichrecording data is data to be recorded continuously in a standard issplit and recording is made intermittently in the split unit.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Preferred embodiments of the present invention will be describedin detail based on the followings, wherein:

[0018]FIG. 1 is a drawing showing a data recording procedure that used aduration for intermittent recording operation in a first embodiment ofthe present invention;

[0019]FIG. 2 is a block diagram of a disc drives in the first embodimentof the present invention;

[0020]FIG. 3 is a drawing showing a disc recording method for describingan operation procedure of the disc drive in the first embodiment of thepresent invention; and

[0021]FIG. 4 is another drawing showing the disc recording method fordescribing the operation procedure of the disc drive in the firstembodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] An embodiment of a data recording method for an optical disc ofthe present invention is shown in FIG. 1.

[0023] In FIG. 1, 101 are a series of recording data to be recordedcontinuously in a standard. For comparison, 105 show the recordingtiming of a conventional disc drive. In the conventional disc drive, asshown in 105, when a part of the data to be recorded in the disc driveis accumulated, the sequentially accumulated data is recordedcontinuously without interrupting recording halfway.

[0024] On the other hand, in this embodiment, as shown in 102, therecording data 101 is split and managed in a fixed recording unit. Forexample, in a DVD-R, the data is split in a unit multiplied by aninteger of an ECC block unit and recorded. In FIG. 1, the data is splitinto ten of A to J as an example. The split recording data 102 of the Ato J that was split is split and recorded intermittently at the timingshown in 103. The reason why the recording period of each split databecomes shorter than the width of each split data is that recording ismade by accumulating the recording data input to a disc drive in a databuffer once and subsequently fetching the data from the data buffer atthe speed that exceeds the input speed of the data input to the databuffer of the disc drive.

[0025] When real time data, such as a video and an audio, is recorded,because the speed of the data recorded in the disc is faster than theinput speed of the data input to the data buffer, intermittent recordingis enabled. A recording duration can be provided in the intervalsbetween the recording and the recording of each split data by making theintermittent recording shown in 103. 104 shows the timing at whichrecorded data is reproduced and the recording quality is estimated usinga part of this recording duration. FIG. 1 shows that each split data ofA to I recorded near by respectively, for example, immediately beforeeach split data 102 of B to J is recorded and the recording quality isevaluated. Thus, because the recording quality of recorded data can beevaluated using a recording duration while a series of data is beingrecorded, the result can be reflected in the laser output adjustment ofthe next data recording. Accordingly, data can be maintained in goodrecording quality over a series of the whole data. Hereupon, it isevaluated that the data recording quality is checked and evaluated andthe recording state is judged, analyzed, and investigated.

[0026] Further, the function of each part inside the disc drive can bestopped in course of a recording duration. This suppresses the powerconsumption of the whole disc drive and makes the temperature riseinside the disc drive slow, thereby enabling the suppression of atemperature rise and use of laser for a long time under good temperaturecharacteristics.

[0027] However, there is the point at issue that because a series ofdata is not recorded continuously as specified in a standard, linkrecording is made every split unit, thereby generating a joint.

[0028] However, concerning this, in the link recording technology usedin a disc drive usually at present, recorded data and the data linkedwith it can realize the link recording with an error of several bytes.Further, the error caused by the link recording is within the range inwhich data is sufficiently corrected with an error correction symbolrecorded at the same time when the data is recorded. Accordingly, therecorded data can be reproduced in the same manner when recording wasmade continuously, thereby causing no problem.

[0029] As described above, in the recording method of this embodiment,although a recording joint is generated, the recorded data is reproducedin the same manner when the recording that is made by a conventionaldisc drive was made continuously. Further, because the laser output canbe adjusted so that the recorded data can meet a periodically suitablerecording condition, good recording quality is obtained over a series ofthe whole data to be recorded. Further, because the temperature riseinside the disc drive can be suppressed by stopping the function of eachpart in course of intermittent recording operation by the intermittentrecording operation, laser can be used under good temperaturecharacteristics even in the recording that lasts for a long time, thegood recording quality can be maintained.

[0030] Accordingly, the recording method and drive of this embodimentare suitable for a low-priced disc drive and a portable compact discdrive that cannot mount a cooling means, such as a fan. Further, thesedisc drives are useful because in most cases, the recording time lastsfor a long time and recording can be made under a stable recordingcondition concerning real time recording, such as a video and an audio,that will not be undone. Further, even in the case of non-real timerecording, because recording quality is maintained satisfactorily evenif recording is made for a long time, those disc drives are alsosuitable for the recording into a Write Once medium, such as a DVD-R,that can be recorded only once.

[0031] Besides, in a standard, a series of data to be recordedcontinuously indicates the data in such recording method as this Disc atOnce. Accordingly, for example, even for a medium, such as a DVD-RW,that enables rewriting, the same case applies when the Disc at Oncerecording is applied. In the Disc at Once recording in which data is aseries of data to be recorded continuously regardless of which medium,the same case applies when a series of data is split and recorded andthe split and recorded data is recorded continuously as a result.Further, the reason why a series of data is split and recorded is thatthe laser output that records data in an intermittent recording periodis adjusted and good recording quality is maintained over the wholesurface of an optical disc.

[0032] Hereupon, the adjustment of the laser output that records theabove data can also be the adjustment of the power and the length of thelaser irradiation time or their combination.

[0033] Further, an advantage of the recording method of this embodimentis that recording quality is evaluated in the vicinity of the area inwhich recording is made actually. This is suitable for corresponding tothe dispersion of recording sensitivity on a disc surface. Further, whenthe recording quality is evaluated, a test pattern is not recorded, butthe recording quality is evaluated according to the data recordedactually. Accordingly, whenever the recording quality is evaluated,because a recording head needs to move to the test write area and thetest pattern needs to be recorded, the recording quality can beevaluated in an extremely short time. Further, because the positioningof the head into the recording start position is performed byreproducing the data recorded nearby, for example, immediately beforeeach split data is recorded, thereby enabling efficient processing.Concerning an actual recording quality evaluation method, error rates,jitters, and asymmetries of the reproduction data used usually in aconventional disc drive ought to be measured.

[0034] A means for implementing the recording method of this embodimentshown in FIG. 1 is shown in FIG. 2 below.

[0035]FIG. 2 shows a part of the configuration of a general disc drive.Because the present invention relates to a recording method, therecording method is implemented by inventing the control methodaccording to the configuration of a conventional disc drive.Accordingly, an explanation of the configuration concerning the wholedisc drive is omitted and an implementation means of this embodiment isdescribed using only the site related to this embodiment.

[0036] In FIG. 2, 201 is a data buffer. The data buffer temporarilyaccumulates data input to a disc drive until it records the data in adisc. Further, the data buffer temporarily accumulates the datareproduced from the disc when it sends the data to a host machineconnected to the disc drive. Besides, the data buffer 201 consists ofmany memories and has the configuration in which data is input to andcan be output from them. 202 is a digital signal processing mean(hereinafter referred to as a DSP). The DSP adds error corrections tothe data transferred from the data buffer 201 and encodes the data in adata format for recording the data in the disc actually. Further, theDSP decodes a signal reproduced from the disc, performs errorcorrections, and calculates an error rate of reproduction data at thesame time. Further, the DSP detects an address on the disc based on thereproduction signal from the disc. 203 is a laser driver. The laserdriver drives laser and emits light based on the data transferred fromthe DSP 202. 204 is an optical pickup. The optical pickup mounts thelaser inside and irradiates an optical disc with recording laser beamand reproduction laser beam. Further, the optical pickup detectsreflected light from the disc and converts it to an electrical signal.Further, the optical pickup takes out a part of the laser exit beam andoutputs a monitor signal for monitoring the laser output. 205 is anoptical disc for recording data. 206 is an analog signal processingmeans (hereinafter referred to as an ASP). The ASP adjusts and binarizesthe amplitude and phase of the reproduction signal from the opticalpickup.

[0037]207 is an automatic laser output adjustment means (hereinafterreferred to as an APC). The APC monitors an output monitor signal of thelaser output from the optical pickup 204 and controls a laser driver atany time so as to become the set target output. 208 is a systemcontroller that manages and controls each part inside the disc drive.

[0038] Besides, the DSP 202, the ASP 206, the APC 207, and the systemcontroller 208 can also be circuits or can also be processed usingmicrocomputer software.

[0039] The functions of the system controller 208 concerning thisembodiment are as follows.

[0040] The accumulation amount of the recording data accumulated in thedata buffer 201 is monitored and appropriately records the data in thedisc 205.

[0041] The function stop and function start of each part inside the discdrive or the power on and power off of each part are controlled and thepower consumption of each part is controlled.

[0042] The data recorded nearby is reproduced and an error rate iscalculated by the DSP 202 based on the reproduced data.

[0043] Based on the error rate, an output target value of the laser thatrecords the data followed up by the APC 207 is set.

[0044] Subsequently, FIG. 3 describes the operation of each part forimplementing the recording method of the present invention by the discdrive shown in FIG. 2 giving itself as an example. FIG. 3 shows a statein which the split data 102-A, -B, and -C shown in FIG. 1 aresequentially recorded in continuous areas 304, 305, 306 on the disc 205by the intermittent operation respectively. Besides, the laser outputwhen recording is made in the area 304, (data that is recorded first),is adjusted to appropriate output by previously recording a test patternusing various types of laser output in the test write area on the discin the same manner of a conventional disc drive and reproducing the testpattern. Further, the data recorded in the disc is input from the hostmachine connected to the disc drive.

[0045] First, a series of data to be recorded is transferred from thehost machine to the disc drive. When the specified amount of data isaccumulated in the data buffer 201, the system controller 208 specifiesthis as the split data 102-A. The system controller 208 sends the splitdata 102-A accumulated in the data buffer to the DSP 202 to record thesplit data 102-A and at the same time positions the optical pickup 204in front from the head front of the area 304 on the disc 205 (the feedmechanism of the optical pickup 204 is not shown). Besides, the datatransfer rate from the data buffer 201 to the DSP 202 needs tosufficiently exceed the data transfer rate from the host machine to thedata buffer 201, and in this embodiment, the condition is satisfied.Subsequently, when the position (address) of the optical pickup 204 issequentially detected by the DSP 202 and the optical pickup 204 reachesthe head of the area 304 on the disc 205, the laser driver 203 drivesthe optical pickup 204 based on the recording data output from the DSP202 and the split data 102-A is recorded in the area 304 on the disc205.

[0046] When the split data 102-A is recorded in the area 304 on the disc205, the system controller 208 stops the function of each part thatought to operate even at recording or reproduction except the databuffer 201 that receives the data from the host machine or turns off thepower. This generates a recording duration. As a result, the recordingstate of 301 shown in FIG. 3 occurs.

[0047] The data from the host machine is accumulated in the data buffer201 even in the recording duration. Subsequently, when the data reachesa specified amount again, the system controller 208 specifies this asthe split data 102-B. To record this, the split data 102-B istransferred to the DSP 202. At the same time, the optical pickup 204 ispositioned in front from the head of the area 305 on the optical pickupdisc 205, that is, in the vicinity of the end of the area 304. Further,the system controller 208 reproduces a part of the split data 102-Arecorded previously in the area from the vicinity of the end of the area304 to the head of the area 305, calculates an error rate by the DSP202, and judges whether the error rate is within the specified range ornot. When the error rate is beyond the specified range, a target outputvalue of the laser followed up by the APC 207 is updated in accordancewith the numerical value.

[0048] Subsequently, when the optical pickup 204 reaches the head of thearea 305 on the optical disc 205, the split data 102-B is recorded inthe area 305 on the optical disc 205 actually. As a result, therecording state of 302 shown in FIG. 3 occurs.

[0049] When the split data 102-B is recorded in the area 305 on the disc205, the system controller 208 stops the function of each part thatought to operate even at recording or reproduction except the databuffer 201 that receives data from the host machine or turns off thepower. This generates a recording duration again. Subsequently, the datafrom the host machine is accumulated in the data buffer 201 even incourse of a recording duration. Then when the data reaches a specifiedamount again, the system controller 208 specifies this as the split data102-C. To record this, the split data 102-C is transferred to the DSP202. At the same time, the optical pickup 204 is positioned in frontfrom the head of the area 306 on the optical pickup disc 205, that is,in the vicinity of the end of the area 305. Then the system controller208 reproduces a part of the split data 102-B recorded previously in thearea from the vicinity of the end of the area 305 to the head of thearea 306, calculates an error rate by the DSP 202, and judges whetherthe error rate is within the specified range. When the error rate isbeyond the specified range, a target output value of the laser followedup by the APC 207 is updated in accordance with the numerical value.

[0050] Subsequently, when the optical pickup 204 reaches the head of thearea 306 on the optical disc 205, the split data 102-C is recorded inthe area 306 on the optical disc 205 actually. As a result, therecording state of 303 shown in FIG. 3 occurs.

[0051] When the split data 102-C is recorded in the area 306 on the disc205, the system controller 208 stops the function of each part thatought to operate even at recording or reproduction except the databuffer 201 that receives data from the host machine or turns off thepower. This generates a recording duration again.

[0052] In FIG. 3, the recording quality of the data recorded nearby wasevaluated before each split data is recorded, but, as shown in FIG. 4,the recording quality can also be evaluated by reproducing a part of thedata of which the recording is just finished immediately after eachsplit data is recorded. However, although the recording quality can beevaluated even in the procedure shown in FIG. 4, the operation in whichthe optical pickup is moved after the recording is finished to reproducethe recording data is required.

[0053] On the contrary, the recording quality is evaluatedintermediately before each split data shown in FIG. 3. Because this canserve both as the operation in which an optical pickup is positioned inthe recording start position, processing efficiency is good. Further,both the recording methods shown in FIGS. 3 and 4 reflect the recordingquality of the data recorded in the past (for the duration) in therecording condition for new recording. Accordingly, when the possibilityof a sudden temperature change occurring in course of the duration needsto be considered, whether temperature is monitored by a temperaturesensor and the recording quality of the data recorded in the past isreflected in the recording condition of new recording according totemperature conditions ought to be determined.

[0054] The procedure in which the split data 102-A, -B, and -C shown inFIG. 1 are sequentially recorded in the areas 304, 305, 305, and 306shown in FIGS. 3 and 4 according to the intermittent operation by thedisc drive shown in FIG. 2 is described. The data of the split data102-D and later shown in FIG. 1 are also recorded by repeating the aboveoperation in the same manner. Subsequently, because the recording datais adjusted so that the laser output can be suitable every recording ina split data unit, better recording quality is maintained. Further,because the data used to evaluate recording quality is in the vicinityof an area in which data is about to be recorded, it can correctlyremove the recording sensitivity dispersion on the disc surface.

[0055] Moreover, because a duration is provided and the power control ofeach part inside a disc drive is enabled in that duration, thetemperature rise inside the disc drive can be suppressed. This can uselaser with good temperature characteristics even if the recording lastsfor a long time and can maintain good recording quality over the wholedata to be recorded.

[0056] Besides, in the above description, every time split data isrecorded, the laser output was adjusted. However, to prevent ameasurement error, the recording in which multiple recording qualitymeasurement results are collectively evaluated and the laser output isadjusted when split data is recorded once multiple times ought to beperformed. Further, a temperature sensor is provided in the disc drive.If the temperature in the vicinity of laser can be measured, the outputought also be adjusted with reference to a temperature change width fromthe preceding adjustment when the laser output is adjusted.

What is claimed is:
 1. An optical recording method that splits andintermittently records a series of data in an optical disc, comprisingthe steps of: splitting a series of data to be recorded continuously;recording split data; reproducing recorded data at the period at whichrecording is interrupted until the next split data is recorded;adjusting the output of laser that records the next split data based ona reproduction signal of reproduced data; and recording a series of datacontinuously by repeating the step in which the output of said recordingand reproduction laser is adjusted.
 2. The optical disc recording methodaccording to claim 1, wherein reproduced data is the data recorded inthe vicinity of a position in which the next split data is about to berecorded.
 3. The optical recording method according to claim 1, whereinthe temperature of a disc drive is monitored and whether informationabout the reproduction signal of said reproduced data is used for theadjustment of laser output or not is also judged based on thetemperature change width.
 4. The optical disc recording method accordingto claim 1, wherein a series of data to be recorded continuously is aseries of data to be recorded continuously in a standard that specifiesan optical disc recording method, and this data is split.
 5. The opticaldisc recording method according to claim 1, wherein the function of eachpart of a disc drive is stopped or disconnecting the power at a periodat which recording is not made by intermittent recording.
 6. The opticaldisc recording method according to claim 5, wherein control is performedso that laser can be used under good temperature characteristics bymaking the temperature of a disc drive.
 7. An optical disc drive thatrecords a series of data in an optical disc, comprising: a means forsplitting a series of data to be recorded continuously; a means forrecording a series of data by intermittently repeating link recording ina split data unit; a means for reproducing recorded split data at aperiod at which recording is not made by intermittent recording; and ameans for adjusting the output of laser that records the next split databased on a reproduction signal of reproduced data.
 8. The optical discdrive according to claim 7, wherein a series of data is recordedcontinuously by intermittently recording and reproducing said series ofdata and repeating the adjustment of the laser output.
 9. The opticaldisc drive according to claim 7, wherein reproduced data is the datarecorded in the vicinity of a position in which the next split data isabout to be recorded.
 10. The optical disc drive according to claim 7,wherein, at a period at which recording is not made by intermittentrecording, said reproduced data is the data recorded intermediatelybefore and the output of the laser that makes the next recording basedon a reproduction signal of the reproduction data in the data recordedintermediately before.
 11. The optical disc drive according to claim 7,wherein an optical disc is a medium that enables writing only once. 12.The optical disc drive according to claim 7, wherein the data recordedin an optical disc is real time data, such as a video and an audio. 13.The optical disc drive according to claim 7, further comprising: a meansfor monitoring the temperature of a disc drive, wherein said adjustmentmeans judges whether the reproduction signal of said reproduced data isused for the adjustment of laser output according to this temperaturechange width.
 14. The optical disc drive according to claim 7, wherein aseries of data to be recorded continuously is a series of data to berecorded continuously in a standard that specifies an optical discrecording method, and this data is split.
 15. The optical disc accordingto claim 7, wherein the function of each part of a disc drive is stoppedor the power is disconnected at a period at which recording is not madeby intermittent recording.